Thinking people always contest with one another as to whether they have all the facts, whether they are interpreting the facts correctly, or whether the facts are relevant to the decisions that need to be made. Unfortunately, we are often not well schooled in the mechanisms and cadences of effective dispute. Emotion becomes the energy behind a debate. Rationality, willingness to accept the incompleteness of our knowledge and humility give way to overconfidence and hubris. Sometimes it is science - what do we really know about global warming versus the wild claims from both sides? Sometimes is it economics - what are the appropriate actions to take in the wake of an asset bubble deflation? Almost always it is really just opinion and loud shouts.
It is refreshing sometimes to look back on past debates. Not how they were resolved, though that is of course interesting. Rather, what is interesting is what we have forgotten about how they began and what was thought to be known at the time with complete certainty.
Brian Switek has an interesting blog post, Ancient Armored Whales, on a long ago and long forgotten debate from the turn of the last century when paleontologists debated heatedly with one another as to whether ancient whales were armored. It makes us smile now, but these were not stupid people. Just overconfident in their facts or their interpretations. We can only smile if we are confident we have learned the lesson of humility about our facts and interpretations. Nothing I see suggests that we have.